Churches can and do make visitors adhere to dress code; I have a photo in Milan of a woman in bare shoulders and an above-the-knees skirt being denied admission into the Milan Duomo and arguing about it. The police or security or whoever they are would not budge.

Wear comfortable shoes- you can do an awful lot of walking in Italy.

Bus tickets are bought in tabacchi shops.

Don't buy the fake purses you'll see for sale on dropclothes in the street in Venice.

Don't be afraid to skip a place that you know you don't have any interest in. For example, my dad and I skipped the Uffizi in Florence. Art museums are my idea of hell on earth.

The Natural History Museum in Venice is truly wonderful; we spent a good 90 minutes there and we coudln't read half the signs. Venice is very walkable and the only time we took a vaporetto is when we went over to Lido and back.

We always checked out the prices and menus before going in and were never horrendously disappointed in our food.

Be aware that there are no free refills on water, soda, etc.

The Pantheon in Rome is free and I loved visiting the Castel Sant'Angelo.

If you're going with a travel group I don't know how much time you'll have for going around on your own, but -

In Florence there is a small museum called "The History of Science" which showcases the Medicis' science collections. Their star exhibit is Galileo's finger. It's a cool museum in you're into science.

There is a very small village in Tuscany called Lucca which is one of the most charming places I've ever been. You can walk around the old city which has around 600 churches, or tour the city walls by foot or by bike. After dinner we were walking around Lucca when we noticed people entering a church, we followed and were treated to an amazing acapella concert with fabulous acoustics inside the old church - so keep your eyes and ears open for something unexpected like that.

Do you like wine? Red wine in Italy is ridiculously cheap and for some reason not as heavy as in other places (it didn't have the added effect of putting me to sleep is what I mean). Enjoy it!

I found Milan to be rather dull, it's a very industrial city with not many places of interest. There was a great Botero sculpture outside the Duomo, but I don't know if it's still there.

Shops close very early in Europe (7PM weekdays, 6PM weekends, Sunday many are closed) so bear that in mind if you plan on doing some shopping.

Forgive me if you already know this, but the weather in Italy in October can be very changeable, so I'd recommend bringing layers and at least one warm sweater plus a raincoat. I was in Ravello and Capri a few Octobers ago, and there were a couple of very hot days when I was able to sunbathe on the beach in a bikini, and one day when I needed to go and buy a coat because it was so cold and rainy (albeit there was a terrible storm that day). At the same time there was light snow in Milan.

If you travel by train, you have to 'validate' your ticket before you get on the train. At train stations there are chunky yellow boxes and basically you stick the ticket in there and it stamps it with the date and time. This is because many train tickets aren't for an exact date, so it's to stop people re-using their ticket. If your ticket is a reservation for an exact train (like the Eurostar) generally you don't have to validate it. http://blog.venezialodging.it/ticket-validation/

If you are Catholic or have Catholic friends, some churches sell very beautiful and inexpensive rosaries made from Murano glass beads. Venice is famous for Murano glass.